INTENSE HEAVY ION BEAM PRODUCTION WITH ECR SOURCES

An average increase of about one order of magnitude per decade in the performance of ECR ion sources was obtained since the time of pioneering experiment of R. Geller at CEA, Grenoble; this trend is not deemed to saturate at least in the next decade, according to the increased availability of powerful magnets and microwave generators. Electron density above 1013 cm-3 can be obtained by 28 GHz microwave heating, but only an adequate plasma trap may allow to exploit that plasma for heavy elements ionization. The optimization of the magnetic field and of the other different parameters affecting the ECRIS plasma has been carried out in the past and more recently a special emphasis was given to the coupling of microwaves to plasma. The state-of-the-art of ECR ion sources will be presented along with long-term perspectives related to the possibilities opened by higher frequency generators, as 60 GHz gyrotrons, even in case of moderate confinement trap, by combining the large plasma density with larger escape rates in order to get very high ion beam currents